Calcium, Chemical Element - structure, reaction, water, uses, elements, examples, metal, gas CAL-cee-um Discovery and naming It is impossible to say when humans first knew about or used compounds of calcium. Whenever they used limestone to build a structure, they were using a compound of calcium. Limestone is the common name for calcium carbonate (CaCO 3 ). Whenever humans built a statue or monument out of marble, they were using calcium carbonate in another form. Ancient Egyptians and early Greeks used mortar, a cement-like material that holds stones and bricks together. Early mortar was made by roasting or heating limestone for long periods of time. Water was then mixed with the powder, which would then dry to form a strong bond. Humphry Davy | English chemist H umphry Davy (1788-1829) was a major contributor to the field of electrochemistry. This is the science involving the relation of electricity to chemical changes. He is best known for discovering calcium, sodium, potassium, magnesium, strontium, and barium. He also discovered nitrous oxide and two types of lamps. Davy grew up in Cornwall, England, in a poor family.

His father, who died when Davy was a boy, had lost money in unwise investments, so Davy helped his mother pay off the debts. He disliked being a student, though he liked reading about science. In later life, he said he was happy he did not study too hard because he had more time to think on his own. With no money for further education, the 17-year-old Davy began to work for a surgeon-pharmacist. He also started learning on his own about other subjects that interested him, such as geography, languages, and philosophy. He even wrote poems that later earned him the respect and friendship of William Wordsworth, Samuel Coleridge, and other leading English poets of his time! At 19, Davy read a chemistry book by the famous French scientist Antoine-Laurent Lavoisier (1743-94). That book convinced him to concentrate on chemistry. For the rest of his life, Davy's career was marked by brilliant scientific explorations in chemistry and electrochemistry. Davy discovered nitrous oxide after testing the effects of hydrogen and carbon dioxide on himself.

(He liked to use himself as a human guinea pig!) Nitrous oxide is a gas consisting of nitrogen and oxygen. While studying nitrous oxide gas, he discovered that its effects often made him feel very happy or very sad. The feeling of happiness eventually gave nitrous oxide another name: laughing gas. Most importantly, though, Davy recognized that it could be used as an anesthetic. An anesthetic is a chemical used to dull pain during minor surgery. In 1808, Davy invented the carbon arc lamp. He had proposed using carbon as the electrode material instead of metal. (Electrodes are conductors used to establish electrical contact with a nonmetallic part of a circuit.) With carbon electrodes, he made a strong electric current leap from one electrode to the other. This created an intense white light. Davy's invention marked the beginning of the era of electric light. Arc lamps are still used today. Using his knowledge of electricity, Davy built a large battery which he used to break down substances most scientists thought were pure elements. In 1807, he discovered the element potassium. He created this by using electrolysis. Electrolysis produces chemical changes by passage of an electric current through an electrolyte.

An electrolyte is a nonmetallic electric conductor. Within a week he isolated sodium in a similar way. Then in 1808, he used a slightly modified method to isolate calcium, magnesium, barium, and strontium. Davy was only 29 by the time he had discovered all of these elements! Davy later invented the miner's lamp (now known as the Davy lamp). He learned that methane was the mine gas that caused explosions. But he realized it ignited only at high temperatures. So he designed a lamp in which the flame was surrounded by wire gauze. This reduced the heat and prevented flammable gases from igniting. This made coal-mining safer by reducing the number of explosions in mines. Davy was rewarded by many honors and medals for his discoveries and inventions. He died of a stroke in 1829 at the age of 49. Another calcium compound used by early civilizations was plaster of paris. Plaster of paris is made by heating gypsum, or calcium sulfate (CaSO 4 ), to remove the water that makes it crystallize. Water was added and it hardened into a brittle, cement-like substance.

Until recently, it was most often used to make casts to protect broken bones. However, it has largely been replaced by fiberglass, which is lighter, yet stronger. The first mention of plaster of paris to protect broken bones can be found in a book written by Persian pharmacist Abu Mansur Muwaffaw in about 975 A.D. By the 1700s, chemists had learned a great deal about calcium compounds. They knew that limestone, gypsum, marble, and many other commonly occurring compounds all contain a common element. They called the element calx. That word comes from the Latin term for lime. In 1807, Davy isolated the new element. Davy invented a system for melting compounds of elements that were difficult to separate by usual methods. He passed an electric current through the compound, causing the compounds to break into parts. One of those parts was calx. He created the name calcium by adding the suffix -ium to calx; -ium is the ending used for almost all metallic elements. Davy was also able to produce free sodium, potassium, strontium, magnesium, and barium. Physical properties Calcium is a fairly soft metal with a shiny silver surface when first cut.

The surface quickly becomes dull as calcium reacts with oxygen to form a coating of white or gray calcium oxide. Calcium's melting point is 850°C (1,560°F) and its boiling point is 1,440°C (2,620°F). It has a density of 1.54 grams per cubic centimeter. Chemical properties Calcium is a moderately active element. It reacts readily with oxygen to form calcium oxide (CaO): Calcium reacts with the halogens— fluorine, chlorine, bromine, iodine, and astatine, The halogens are the elements that make up Group 17 (VIIA) of the periodic table. Calcium also reacts readily with cold water, most acids, and most nonmetals, such as sulfur and phosphorus. For example, calcium reacts with sulfur: Occurrence in nature Calcium is the fifth most common element in the Earth's crust. Its abundance is estimated to be about 3.64 percent. It is also the fifth most abundant element in the human body. Calcium does not occur as a free element in nature. It is much too active and always exists as a compound.

The most common calcium compound is calcium carbonate (CaCO 3 ). It occurs as aragonite, calcite, chalk, limestone, marble, and travertine, and in oyster shells and coral. Shellfish build their shells from calcium dissolved in the water. When the animals die or are eaten, the shells sink. Over many Calcium carbonate can be found in coral. centuries, thick layers of the shells may build up and be covered with mud, sand, or other materials. The shells are squeezed together by the heavy pressure of other materials and water above them. As they are squeezed together, the layer is converted to limestone. If the limestone is squeezed even more, it can change into marble or travertine. Isotopes Six naturally occurring isotopes of calcium exist: calcium-40, calcium-42, calcium-43, calcium-44, calcium-46, and calcium-48. Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element's name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element.

The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope. Radioactive isotopes of calcium have also been made. A radioactive isotope is one that breaks apart and gives off some form of radiation. Radioactive isotopes are produced when very small particles are fired at atoms. These particles stick in the atoms and make them radioactive. Two radioactive isotopes of calcium are used in research and medicine. Calcium-45 is used to study how calcium behaves in many natural processes. For example, it can be used to see how various types of soil behave with different kinds of fertilizers. The calcium-45 is used as a tracer in such studies. A tracer is a radioactive isotope whose presence in a system can easily be detected. The isotope is injected into the system at some point. Inside the system, the isotope gives off radiation. That radiation can be followed by detectors placed around the system. Calcium-45 can also be used as a tracer in the study of glassy materials, detergents, and water purification systems. Both calcium-45 and calcium-47 can be used to study how calcium is used in the body.

A doctor may think that a person's body is not using calcium properly in making bones or regulating nerve messages. The doctor can use calcium-45 or calcium-47 to find out more about this problem. The radioactive isotope is injected into the person's bloodstream. Then its path can be followed by the radiation it gives off. The doctor can then tell if the calcium is being used normally in the body. Extraction Pure calcium metal can be made by the same method used by Davy. An electric current is passed through molten calcium chloride: There is not much demand for pure calcium. Most calcium is used in the form of limestone, gypsum, or other minerals that can be mined directly from the earth. Shellfish build their shells from calcium dissolved in the water. Uses Calcium metal has relatively few uses. It is sometimes used as a "getter." A getter is a substance that removes unwanted chemicals from a system. Calcium is used as a getter in the manufacture of evacuated glass bulbs. Calcium is added to the Calcium carbonate, as seen in the White Cliffs of Dover, England. bulb while it is being made. It then combines with gases left in the glass in the final stages of manufacture.

Calcium is also used as a getter in the production of certain metals, such as copper and steel. The calcium removes unwanted elements that would otherwise contaminate the metal. Calcium is also used to make alloys. An alloy is made by melting and mixing two or more metals. The mixture has properties different from those of the individual metals. An alloy of calcium and cerium is used in flints found in lighters (the elements that create sparks). Compounds The starting point for the manufacture of most calcium compounds is limestone. Limestone occurs naturally in large amounts in many parts of the world. It is usually mined from open-pit quarries. A quarry is a large hole in the ground from which useful minerals are taken. Limestone is first heated to obtain lime, or calcium oxide (CaO): Lime is one of the most important chemicals in the world. It usually ranks in the top five chemicals produced in the United States. In 1996, about 19 billion kilograms (42 billion pounds or 21 million tons) of lime was produced in the United States. Lime is used in the production of metals.

It is used during the manufacture of steel to remove unwanted sand, or silicon dioxide (SiO 2 ), present in iron ore: The product formed in this reaction, calcium silicate (CaSiO 3 ), is called slag. Another important use of lime is in pollution control. Many factories release harmful gases into the atmosphere through smokestacks. Lining a smokestack with lime allows some of these gases to be captured. The lime is known as a scrubber. Lime captures one harmful gas, sulfur dioxide (SO 2 ), which is a contributor to acid rain (a form of precipitation that is significantly more acidic than neutral water, often produced as the result of industrial processes): Calcium sulfite (CaSO 3 ) is a solid that can be removed from the inside of the smokestack. "In the limelight" At one time, lime was used as a source of light in theaters. When lime is heated to a high temperature, it gives off an intense white light. Pots of hot lime were often used to line the front of the stage. The light the pots gave off helped the audience see the performers.

As a result, the performers were said to be "in the limelight." That phrase is still in use today, but lime is no longer used as a source of light in theaters. Lime is also used in water purification and waste treatment plants. When water combines with water, it forms slaked lime, or calcium hydroxide (Ca(OH) 2 ): Slaked lime traps impurities present in the water as it forms. It carries the impurities with it as it sinks to the bottom of the tank. Lime is used to make more than 150 different industrial chemicals. Some examples of these chemicals with their uses are: Milk is a good source of calcium.

calcium alginate: thickening agent in food products such as ice cream and cheese products; synthetic fibers calcium arsenate (Ca 3 (AsO 4 ) 2 ): insecticide calcium carbide (CaC 2 ): used to make acetylene gas (for use in acetylene torches for welding); manufacture of plastics calcium chloride (CaCl 2 ): ice removal and dust control of dust on dirt roads; conditioner for concrete; additive for canned tomatoes; provides body for automobile and truck tires calcium cyclamate (Ca(C 6 H 11 NHSO 4 ) 2 ): sweetening agent (cyclamate), no longer permitted for use because of suspected cancer-causing properties calcium gluconate (Ca(C 6 H 11 O 7 ) 2 ): food additive; vitamin pills calcium hypochlorite (Ca(OCl) 2 ): swimming pool disinfectant; bleaching agent; deodorant; algicide and fungicide (kills algae and fungi) calcium permanganate (Ca(MnO 4 ) 2 ): liquid rocket propellant; textile production; water sterilizing agent; dental procedures calcium phosphate (Ca 3 (PO 4 ) 2 ): supplement for animal feed;

 fertilizer; commercial production of dough and yeast products; manufacture of glass; dental products calcium phosphide (Ca 3 P 2 ): fireworks; rodenticide (kills rats); torpedoes; flares calcium stearate (Ca(C 18 H 35 O 2 ) 2 ): manufacture of wax crayons, cements, certain kinds of plastics, and cosmetics; food additive; production of water resistant materials; production of paints calcium tungstate (CaWO 4 ): luminous paints; fluorescent lights; X-ray studies in medicine Health effects Calcium is essential to both plant and animal life.

In humans, it makes up about two percent of body weight. About 99 percent of the calcium in a person's body is found in bones and teeth. Milk is a good source of calcium. The body uses calcium in a compound known as hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ) to make bones and teeth hard and resistant to wear. Calcium has many other important functions in the human body. For example, it helps control the way the heart beats. An excess (too much) or deficiency (not enough) of calcium can change the rhythm of the heart and cause serious problems. Calcium also controls the function of other muscles and nerves. Also read article about Calcium from Wikipedia User Contributions: Calcium»historical information [WebElements Periodic Table] Calcium: historical information Calcium: historical information Calcium was discovered by Sir Humphrey Davy at 1808 in England. Origin of name : from the Latin word "calx" meaning "lime" Compounds such as lime (CaO, calcium oxide) were prepared by the Romans in the first century under the name calx.

Literature dating back to about 975 AD notes that plaster of paris (calcium sulphate, CaSO4, dehydrated gypsum) is useful for setting broken bones. Other calcium compounds used in early times include limestone (CaCO3, calcium carbonate). Calcium metal was not isolated until 1808. After learning that Berzelius and Pontin prepared calcium amalgam by electrolysing lime in mercury, Sir Humphry Davy was able to isolate the impure metal. He did this by the electrolysis of a mixture of lime and mercuric oxide (HgO). Calcium metal was not available in large scale until the beginning of the 20th century. Sometime prior to the autumn of 1803, the Englishman John Dalton was able to explain the results of some of his studies by assuming that matter is composed of atoms and that all samples of any given compound consist of the same combination of these atoms. Dalton also noted that in series of compounds, the ratios of the masses of the second element that combine with a given weight of the first element can be reduced to small whole numbers (the law of multiple proportions). This was further evidence for atoms.

Dalton's theory of atoms was published by Thomas Thomson in the 3rd edition of his System of Chemistry in 1807 and in a paper about strontium oxalates published in the Philosophical Transactions. Dalton published these ideas himself in the following year in the New System of Chemical Philosophy. The symbol used by Dalton for calcium is shown below. [See History of Chemistry, Sir Edward Thorpe, volume 1, Watts & Co, London, 1914.] WebElements chemistry shop You can buy periodic table posters, mugs, T-shirts, periodic table fridge magnets, games, molecular models, and more at the WebElements periodic table shop Potassium»historical information [WebElements Periodic Table] Potassium: historical information Potassium: historical information Potassium was discovered by Sir Humphrey Davy at 1807 in England. Origin of name : from the English word "potash" (pot ashes) and the Arabic word "qali" meaning alkali (the origin of the symbol K comes from the Latin word "kalium") Until the 18th century no distinction was made between potassium and sodium.

This was because early chemists did not recognise that "vegetable alkali" (K2CO3, potassium carbonate, coming from deposits in the earth) and "mineral alkali" (Na2CO3, sodium carbonate, derived from wood ashes) are distinct from each other. Eventually a distinction was made. Well before potassium was recognized as an element, potassium carbonate was mixed with animal fat to make soap. The carbonate was made by extracting wood ash with water before concentration by boiling - hence the name "potash" for potassium salts. Potassium was isolated in 1807 by Sir Humphry Davy, who obtained it through the electrolysis of very dry molten caustic potash (KOH, potassium hydroxide). Potassium collected at the cathode. Potassium was the first metal isolated by electrolysis. Davy isolated sodium by a similar procedure later in 1807. Sometime prior to the autumn of 1803, the Englishman John Dalton was able to explain the results of some of his studies by assuming that matter is composed of atoms and that all samples of any given compound consist of the same combination of these atoms.

Dalton also noted that in series of compounds, the ratios of the masses of the second element that combine with a given weight of the first element can be reduced to small whole numbers (the law of multiple proportions). This was further evidence for atoms. Dalton's theory of atoms was published by Thomas Thomson in the 3rd edition of his System of Chemistry in 1807 and in a paper about strontium oxalates published in the Philosophical Transactions. Dalton published these ideas himself in the following year in the New System of Chemical Philosophy. The symbol used by Dalton for potassium is shown below. [See History of Chemistry, Sir Edward Thorpe, volume 1, Watts & Co, London, 1914.] WebElements chemistry shop You can buy periodic table posters, mugs, T-shirts, periodic table fridge magnets, games, molecular models, and more at the WebElements periodic table shop Chemistry for Kids: Elements - Sodium Sodium 0.968 grams per cm cubed Melting Point: Discovered by: Sir Humphry Davy in 1807 Sodium is an alkali metal located in the first group or column of the periodic table.

The sodium atom has 11 electrons and 11 protons with one valence electron in the outer shell. Characteristics and Properties Sodium in its pure form is very reactive. It is a very soft metal that can be easily cut with a knife. It is silvery-white in color and burns with a yellow flame. Sodium will float on water, but it will also react violently when coming into contact with water. When sodium reacts with water it produces sodium hydroxide and hydrogen gas. Sodium is most famous for its many useful compounds such as table salt (NaCl), sodium nitrate (Na2CO3), and baking soda (NaHCO3). Many of the compounds that sodium forms are water-soluble, meaning they dissolve in water. Where is sodium found on Earth? Sodium is the sixth most abundant element on Earth. It is never found in its pure form because it is so reactive. It is only found in compounds such as sodium chloride (NaCL) or table salt. Sodium chloride is found in ocean water (salt water), salt lakes, and underground deposits. Pure sodium can be recovered from sodium chloride through electrolysis. How is sodium used today?

Sodium is primarily used in the form of compounds with other elements. The average person uses sodium every day in the form of table salt in their food. Table salt is the compound sodium chloride (NaCl). Table salt is needed for animals to survive, but most people use it for adding flavor to their food. Another popular use of sodium is in baking soda which is the chemical compound sodium bicarbonate. Baking soda is used as a leavening agent in cooking foods like pancakes, cakes, and breads. A lot of soaps are forms of sodium salts. Sodium hydroxide is a key ingredient when making soaps. Other applications include de-icing, medicine, organic chemistry, street lights, and cooling nuclear reactors. How was it discovered? Sodium was discovered by English chemist Sir Humphry Davy in 1807. He isolated sodium by applying electrolysis to caustic soda. Where did sodium get its name? Sodium gets its name from the English word soda. This is because Sir Humphry Davy used caustic soda when isolating the element. The symbol Na comes from the Latin word natrium.

Isotopes Only one of the 20 known isotopes of sodium is stable, sodium-23. Interesting Facts about Sodium Sir Humphry Davy discovered sodium only a few days after he discovered potassium. Sodium comprises around 2.6% of the Earth's crust. It helps to maintain the proper fluid balance in the body's cells and also helps us to digest our food. Our bodies lose sodium when we sweat. However, most people eat far more sodium than their bodies actually need. If the body runs low on sodium, it can cause the muscles to cramp. Sodium is considered non-toxic, but too much of it can cause high blood pressure. More on the Elements and the Periodic Table It's Elemental - The Element Potassium It's Elemental Melting Point: 336.53 K (63.38°C or 146.08°F) Boiling Point: 1032 K (759°C or 1398°F) Density: 0.89 grams per cubic centimeter Phase at Room Temperature: Solid Element Classification: Metal Period Number: 4 Group Number: 1 Group Name: Alkali Metal What's in a name?

From the English word potash. Potassium's chemical symbol comes from the Latin word for alkali, kalium. Say what? Potassium is pronounced as poh-TASS-ee-em. History and Uses: Although potassium is the eighth most abundant element on earth and comprises about 2.1% of the earth's crust, it is a very reactive element and is never found free in nature. Metallic potassium was first isolated by Sir Humphry Davy in 1807 through the electrolysis of molten caustic potash (KOH). A few months after discovering potassium, Davy used the same method to isolate sodium . Potassium can be obtained from the minerals sylvite (KCl), carnallite (KCl·MgCl2·6H2O), langbeinite (K2Mg2(SO4)3) and polyhalite (K2Ca2Mg(SO4)4·2H2O). These minerals are often found in ancient lake and sea beds. Caustic potash, another important source of potassium, is primarily mined in Germany, New Mexico, California and Utah.

Pure potassium is a soft, waxy metal that can be easily cut with a knife. It reacts with oxygen to form potassium superoxide (KO2) and with water to form potassium hydroxide (KOH), hydrogen gas and heat. Enough heat is produced to ignite the hydrogen gas. To prevent it from reacting with the oxygen and water in the air, samples of metallic potassium are usually stored submerged in mineral oil. Potassium forms an alloy with sodium (NaK) that is used as a heat transfer medium in some types of nuclear reactors. Potassium forms many important compounds. Potassium chloride (KCl) is the most common potassium compound. It is used in fertilizers, as a salt substitute and to produce other chemicals. Potassium hydroxide (KOH) is used to make soaps, detergents and drain cleaners. Potassium carbonate (KHCO3), also known as pearl ash, is used to make some types of glass and soaps and is obtained commercially as a byproduct of the production of ammonia.

Potassium superoxide (KO2) can create oxygen from water vapor (H2O) and carbon dioxide (CO2) through the following reaction: 2KO2 + H2O + 2CO2 => 2KHCO3 + O2. It is used in respiratory equipment and is produced by burning potassium metal in dry air. Potassium nitrate (KNO3), also known as saltpeter or nitre, is used in fertilizers, match heads and pyrotechnics. Estimated Crustal Abundance: 2.09×104 milligrams per kilogram Estimated Oceanic Abundance: 3.99×102 milligrams per liter Number of Stable Isotopes: 2 ( View all isotope data ) Ionization Energy: 4.341 eV Science and Celebrity: Humphry Davy's Rising Star | Chemical Heritage Foundation An 1830 engraving of Sir Humphry Davy, by G. R. Newton, after a painting by Sir Thomas Lawrence (1769–1830). Davy stands next to one of his inventions, the miner’s safety lamp. Photograph by Gregory Tobias.

Fisher Collection, CHF Collections. Science and Celebrity: Humphry Davy's Rising Star Working his way up from humble beginnings, Humphry Davy took England by storm, traveling among the scientific and literary elite while dazzling the public with his groundbreaking experiments. Davy using a voltaic battery to experiment with the decomposition of alkalis. Bettmann/Corbis The June air was stifling. But in the Royal Society’s steeply raked amphitheater London’s fashionable men and women, scientists and laymen, crowded the benches and gallery to watch Humphry Davy, the celebrity chemist, present his latest scientific findings. The previous year at the Royal Society’s prestigious Bakerian Prize lecture, Davy had tossed a nugget of metallic potassium into a flask of water, where the lump skittered around the surface of the water before exploding in lavender flames. Expectations for the June lecture were high. The crowd leaned in, anticipating another colorful, if not explosive, performance. With his lively demonstration of electrolysis using a sizable voltaic pile, Davy did not disappoint. The year 1808 was an important one for Humphry Davy.

In that year two centuries ago, Davy discovered five elements: barium, calcium, boron, strontium, and magnesium. He delivered the news of his discoveries to rapt audiences in two captivating lectures—the first in June and another in December—that marked stepping stones in his climb to an apex of scientific and social celebrity status in London. But while Davy enjoyed his celebrity, he also bore gossip, speculation, and criticism as an outsider. Davy’s 1808 discoveries depended on his use of and research into the burgeoning field of electrochemistry, the study of electricity’s effect on chemical reactions. As a young researcher at the Bristol Pneumatic Institute, Davy had caught the fever of excitement over Count Alessandro Volta’s 1800 paper describing what came to be known as the voltaic pile, a sandwich of a damp cardboard disk between two metal disks that generated a weak but continuous charge. Young Davy immediately began to study and experiment with voltaic piles, making batteries out of them, and using the electrical charges to separate elements from their compounds. Davy had contributed to the field by discovering that electricity itself was caused by chemistry.

By the time he arrived in London in 1801, Davy had written six papers on his experiments in electrochemistry. In 1807, using electrochemistry, Davy isolated the metals potassium (from caustic potash, now known to be potassium hydroxide [KOH]) and sodium (from caustic soda, now known to be sodium hydroxide [NaOH]). In 1808 he isolated four of the alkaline earth metals from several mineral mixtures. Davy’s electrolytic apparatus was simple in concept: a battery was connected to metallic electrodes that were dipped into a liquid containing the compound that Davy wanted to decompose into its elements. At first, Davy tried to dissolve various compounds in water, but the water was electrolyzed into hydrogen and oxygen, leaving the investigational compound intact. So Davy melted the minerals he was studying and then alloyed them with mercury before passing the electric current through them. The molten compounds bubbled when the current passed through, producing small clumps of silvery metals on one electrode and liberating gaseous oxygen on the other. The electrodes themselves were inert and did not react chemically with the electrolyte.

Davy extracted pure barium from a substance called “baryte,” which may have been barium oxide (BaO) or barium sulfate (BaSO4). From “lime,” or calcium oxide (CaO), also known as quicklime, he prepared calcium. To isolate strontium he used “strontites,” which may have been a pure strontium oxide (SrO) or the strontium ore from the Strontian region of Scotland, composed primarily of strontium sulfate (SrSO4). Davy’s magnesium was isolated “magnesia,” or magnesium oxide (MgO). Experiments as Entertainment The late 1700s had witnessed the birth of the public scientific lecture, and by 1808 it had become a popular source of entertainment for London’s middle class and elite. Curious men and women would flock to lecture halls to watch as scientists demonstrated the latest discoveries about the properties of electricity, chemical elements, air, and gases. The demonstrations produced sparks, explosions, and unusual odors, all guaranteed to excite the audience.

Davy was an expert at public demonstrations, showing off his own extra-ordinary discoveries and a flare for the theatrical that kept his audience riveted to their seats—and kept them talking about him long after they’d left the lecture hall. For his June 1808 lecture Davy carted one of the Royal Institution’s enormous 600-plate voltaic batteries into the hall to demonstrate electrochemistry for the crowd. Stored in flasks, the molten fluid shimmered in the sunlight, and when the battery was connected to the electrolytic cell, the sudden appearance of metal electroplating one electrode and oxygen effervescing from the other must have seemed like magic. davy-laughing_gas_cartoon.jpg A young Humphry Davy gleefully works the bellows in this caricature by James Gillray of experiments with laughing gas at the Royal Institution. The lecturer is Thomas Garrett, Davy’s predecessor as professor of chemistry. Benjamin Thompson, Count Rumford, the founder of the Royal Institution, stands at the doorway. Photograph by Gregory Tobias. Fisher Collection, CHF Collections. Ladies in the audience twittered at Davy’s fireworks and surreptitiously took notes.

Aristocrats preened and even took turns standing in as Davy’s assistant. He was revered by the audience as a scientific wunderkind. Davy was at the top of his game. But there was another element to his celebrity. Davy was an unlikely star of the Regency period. His humble country beginnings, some early scientific missteps, and a youthful association with political radicals made his London celebrity and aristocratic patronage suspect. He was perceived by some London conservatives as a pretentious social climber, who turned his back on early loyalties in order to curry favor with the Royal Society’s elite. Davy wore rustic clothing, pitched his theatrics toward the women in his audience, and seemed to aspire to a social class to which he did not belong; all this earned him the label of a dandy and a fop. And while the general public revered him for his scientific accomplishments, he was often criticized by the aristocratic and scientific elite. A Self-Starting Student Most scientists of the age were formally educated men of independent wealth. Antoine-Laurent Lavoisier, whose chemistry textbook inspired many of Davy’s early experiments, was a wealthy French nobleman who attended the Collège Mazarin and the University of Paris.

Joseph Banks, who served as president of the Royal Society when Davy presented most of his Bakerian lectures, was born into a wealthy family, owned country estates and lavish town houses, and attended Eton, Oxford, and Christ Church, where he privately paid honoraria for lecturers with whom he wished to study. In contrast Davy’s parents, though from respectable families, were middle-class, and his cobbled-together education, first in Penzance and later in Bristol, was rather informal. As a child Davy was given some formal education, but his desultory studies were largely left to chance. He spent some of his childhood as a ward in the home of John Tonkin, a family friend and surgeon-apothecary, whose shop was a source of the chemicals that Davy regularly pilfered. He created firecrackers using tobacco pipes and teacups as vessels and painted phosphorescent figures on the walls to scare his sisters. Full of mischief, with a penchant for explosions, he was a born chemist.

At age 16, shortly after the death of his father, Davy set out on a course of self-education, and with Tonkin’s help found an apprenticeship with Bingham Borlase, an apothecary in Penzance. In addition to writing poetry and reading up on history, theology, philosophy, and metaphysics, Davy began performing basic chemical research and reading Lavoisier in the original French. He advanced quickly and wrote a manuscript detailing his theories on the material makeup of light. The manuscript expounded on Davy’s “phosoxygen theory,” which proposed that oxygen gas consisted partly of light, and that light itself was made of minute particles. Such a manuscript was a great accomplishment for an apprentice apothecary in backwater Cornwall with no university training, one who had never witnessed a scientific experiment being designed or performed. Full of mischief, with a penchant for explosions, Davy was a born chemist. Although Davy’s education was informal, he began to attract attention and respect from the local academic and social elite. While still an apprentice he met the Sheriff of Cornwall, Davies Gilbert (born Davies Giddy), an Oxford graduate who would later succeed Davy as president of the Royal Society.

Impressed with Davy’s intelligence, Gilbert granted Davy the use of his private library and introduced him to scientists, including Thomas Beddoes, another former Oxford academic. When he met Davy, Beddoes was establishing the Pneumatic Institute, an experimental hospital in Bristol, to study the therapeutic effects of the local “airs” and various gases in the treatment of disease. Of particular interest for Beddoes (and Davy) was nitrous oxide, which many believed spread disease. Others thought it a panacea. The Bristol Set Thomas Beddoes was a learned scholar with a streak of political radicalism. While a chemistry reader at Oxford, he had all-too-publicly sympathized with the aims of the French Revolution. He promulgated its revolutionary ideals by authoring antigovernment pamphlets, even after the gruesome details of the Reign of Terror and its hungry guillotine became known, thus earning himself a reputation as a Jacobin. Beddoes removed to Bristol after the British Home Office had suggested to Oxford that his employment was unwise. In addition to founding the Pneumatic Institute in Bristol, Beddoes associated with other known Jacobins there, such as the Lake Poets Samuel Taylor Coleridge and William Wordsworth.

Beddoes was much taken with Davy and his experiments on light and heat; he read Davy’s manuscript and soon offered him a job. With no formal education, Davy became a researcher at Beddoes’s Pneumatic Institute in 1796 at the age of 18. Davy’s research with Beddoes marked the beginning of his fame and his notoriety. At the Pneumatic Institute Davy lectured about the properties of the gases he isolated, and he showed promise early as a dramatic and compelling lecturer. Through his theatrical lectures and his association with prominent citizens, Davy became known among Bristol society. One of Davy’s early acquaintances was Robert Southey, another of the Lake Poets. Through Southey and Beddoes, Davy later met Coleridge and Wordsworth. He isolated promising gases in his laboratory, especially nitrous oxide, and in the great 18th-century tradition, tested their effects on himself and his friends. Coleridge and Southey, among many others, allowed themselves to be used as drunken human guinea pigs to explore the effects of nitrous-oxide intoxication, and Davy coined the term laughing gas to describe its delights.

In early 1799 Beddoes published a collection of papers that included Davy’s adolescent experiments on light and heat from his apprentice apothecary years in Penzance. The experiments, though intelligent in design, were abysmal in execution, and his conclusions derived more from passion than from scruple. In this publication Davy triumphantly concluded that his phosoxygen theory explained the blue color of the sky, electricity, red color in roses, the aurora borealis, melanin pigmentation in people from Africa, the fire of falling stars, thought, perception, happiness, and why women are fairer than men. The critics lambasted Davy’s work, tearing it apart for its overreaching conclusions that did not follow from empirical evidence. His theories were mercilessly ridiculed and treated with vitriolic contempt. In addition to the attacks on Davy’s adolescent research, Beddoes’s Pneumatic Institute drew fire. A Tory satirical magazine, the Anti-Jacobin Review, published an attack in verse on the Bristol “Pneumatic Revellers,” mocking Beddoes and Davy’s nitrous-fueled bacchanalia.

Davy was humiliated by the reviewers’ hostile response to his youthful article, but he took the criticism to heart and refined his experimental methods. In 1800 he published another better-received work in which he laid out his analysis of the components of nitrous oxide and apologized for his previous scientific missteps. The ridicule of activities at the Pneumatic Institute had made a fool of Beddoes, but although Davy also took some of the punches, his reputation was not ravaged. In fact, Davy’s meticulously researched and sober 1800 book on the composition of gases saved his reputation. Despite his scientific overexuberance, his associations with political radicals, his youthful theatrics, and his questionable experimentation at the Pneumatic Institute, Davy was also gaining recognition as an outstanding scientist. After Thomas Charles Hope, a professor of chemistry at the University of Edinburgh, witnessed Davy’s work at the Pneumatic Institute he recommended to Count Rumford, one of the Royal Institution’s founders, that Davy be brought to London to direct the laboratory and become an assistant lecturer in chemistry. In March 1801 the self-educated country chemist arrived in London to take on Europe’s scientific and social elite.

Moving Up in London Davy’s reception in London was mixed. The London aristocracy was not immediately receptive to Davy’s seemingly rough, provincial ways. Count Rumford himself was reported to have at first found Davy repulsive. But the audiences loved him. On 25 April 1801 Davy delivered his first public lecture at the Royal Institution. His excitement over recent advances in electricity made for a clear choice in subject: Davy’s demonstration was on the power of galvanism, or electricity produced by chemical means, to cause movement in the amputated legs of frogs and to catalyze the isolation of metals from aqueous acids. The lecture was a tremendous success. Davy’s flair for the theatrical, coupled with his scientific advances, brought him accolades, and Coleridge attended, adding to the celebrity cachet. Despite a rustic education, radical political associations, and appearances of social climbing, Davy was well regarded at the Royal Society: he was elected a fellow in 1803 and one of two secretaries in 1807.

By June 1808 Davy was 29 years old, handsome, well-connected, and acknowledged by his peers and most of fashionable society as brilliant. His notoriety as an abuser of nitrous oxide who held onto his coarse country ways only added to his élan. Davy’s flair for the theatrical, coupled with his scientific advances, brought him accolades. Later that same year, two days shy of his 30th birthday, Humphry Davy gave his third Bakerian award lecture in the main theater of the Royal Society. In this lecture Davy announced his discovery of yet another element by the decomposition of boric acid: boron. (That same year boron was also independently isolated by the French chemists Joseph Louis Gay-Lussac and Louis Jacques Thénard.) An Accomplished and Revered Figure After 1808 Davy’s celebrity and notoriety only increased. Davy’s lectures were ever better attended, and he gave five Bakerian award lectures at the Royal Society from 1806 to 1810 and a sixth toward the end of his life in 1826.

In 1812 Davy was knighted, gave a farewell lecture to the Royal Institution, and married a wealthy bluestocking widow, Jane Apreece. Davy’s bride was well known in London’s social and literary circles (she was the cousin of Sir Walter Scott), and the marriage was much discussed among fellow socialites. After a few years the marriage was widely known to be acrimonious and was cause for gossip and ridicule. Also in 1812 a series of laboratory explosions from experiments with nitrogen trichloride caused temporary damage to Davy’s eyesight. He thus hired the young Michael Faraday, a bookbinding apprentice who, like Davy himself, had a great appetite for research but no university training. In 1819 Davy was awarded a baronetcy, an honor unprecedented for a natural philosopher, and in 1820 he became president of the Royal Society, a post he held until he was succeeded by his Cornish benefactor, Davies Gilbert, in 1827. Coleridge wrote of Davy in 1801 that “chemistry tends . . .

to turn it’s [sic] Priests into Sacrifices.” Like Joseph Priestley, another of chemistry’s priests-turned-sacrifice, Sir Humphry Davy eventually left his native England, never to return. He died of heart failure in Switzerland in 1829, at the age of 50. He had become a social celebrity and scientific luminary despite his self-made education and unusual background among London’s academic elite. But he was never entirely able to shed his reputation as a stranger. In fact, Davy’s outsider status—the very fodder for criticism, gossip, and speculation—made him all the more noteworthy to an enraptured public. It may have been the very thing that made him a spectacular star. Davy’s electrochemical experiments, the decomposition and quantification of minerals and other compounds into their fundamental elements, were vital to the development of electrochemistry, including the work of Michael Faraday in the mid-19th century and Walther Nernst, Paul Héroult, and Charles Hall in the late 19th century.

His 1808 lectures unveiling the isolation of barium, strontium, calcium, magnesium, and boron marked a whirlwind moment of theatricality, celebrity, and scientific advance, and an important milestone in the history of chemistry. Barium, Chemical Element - water, uses, elements, metal, number, name, symbol, property Photo by: paulrommer Overview Barium was first isolated in 1808 by English chemist Sir Humphry Davy (1778-1829). In 1807 and 1808, Davy also discovered five other new elements: sodium, potassium, strontium, calcium, and magnesium. All of these elements had been recognized much earlier as new substances, but Davy was the first to prepare them in pure form. (See sidebar on Davy in the Calcium entry.) Barium had first been identified as a new material in 1774 by Swedish chemist Carl Wilhelm Scheele (1742-86). The form with which Scheele worked, however, was a compound of barium, barium sulfate (BaSO 4 ).

Barium sulfate is, in fact, the most common naturally occurring ore of barium. It is generally known as barite or barytes. SYMBOL Pure barium is produced by reacting barium oxide (BaO) with aluminum or silicon: Uses Barium metal has relatively few uses because it is so active. This activity makes it an excellent "getter" or "scavenger" when removing unwanted oxygen from sealed glass containers. (Oxygen can interfere with the operation of a vacuum tube, for example.) By adding a small amount of barium to the tube, the free oxygen inside will be "soaked up." The oxygen reacts with the barium to form barium oxide. Compounds Compounds of barium, especially barite (BaSO 4 ), are critical to the petroleum industry. Barite is used as a weighting agent in drilling new oil wells. A weighting agent is a material that adds body to petroleum. Drilling for oil used to produce huge gushers. A gusher is an oil that sprays out of the well into the air. Gushers are undesirable, because they waste oil and can burn for months if ignited.

Gushers are caused by the pressure of oil rushing into a newly drilled hole in the ground. This pressure pushes the oil upward much too rapidly. Barite is added to the hole as it is drilled. There, it tends to mix with oil in the ground and form a very dense mixture that comes out much more slowly and under control. Ninety percent of the barite mined in the United States is used by the petroleum industry. Here are other uses of barite and other barium compounds: Taking a look inside the body P erhaps the best known use of barium compounds is in medicine. Doctors often want to know what is happening inside a patient's body. One way to find out, of course, is through surgery. But surgery is a drastic procedure. It can cause new problems for the patient. As a result, medical researchers have developed procedures that are less extreme. One such method is called radiography. Radiography is a technique in which X rays are passed through the body. X rays are high energy light waves. They can pass through skin and tissue, but are absorbed by bones. So X rays are a good way of finding out if a bone is broken, for example.

Any type of light appearing on film from an X ray produces a black area, or exposure. The X rays pass through soft issues, exposing the film. Bones look greyish white on the film, depending on how much energy gets through. Radiography can be also be used for studying parts of the body where bones are not involved. For example, a doctor might want to study a person's stomach. Since there are no bones in the stomach, some other method must be used to see inside the stomach. Barium sulfate is often used in such cases. Barium sulfate has some of the same properties as bony material. Therefore, since X rays will not pass through barium sulfate, this compound can be used to examine certain soft tissues. Radiography using barium sulfate is called a barium swallow or a barium enema. Barium sulfate is mixed with water into a slurry (mixture) that looks and tastes like ground-up chalk. The patient swallows the dense mixture. A doctor or nurse then holds a fluoroscope over the patient's abdomen. The fluoroscope emits X rays that show up on a television screen.

The barium sulfate-water mixture slowly travels down the patient's throat, into the stomach, through the intestines, and out through the bowels. As the barium sulfate coats the lining of the digestive tract, a doctor can see if anything is wrong. How can a toxic compound like barium sulfate be used for this procedure? Barium sulfate does not dissolve in water. So it cannot enter the blood stream. If it cannot get into the blood, it has no toxic effects. The barium sulfate is eliminated through the bowels a few hours after the procedure.

barium sulfate (barite): used to add body to or as a coating for paper products; as a white coloring agent in paints, inks, plastics, and textiles; in the manufacture of rubber products; in the production of batteries; in medical applications (see accompanying sidebar) barium carbonate (BaCO 3 ): used in the production of chlorine and sodium hydroxide; as rat poison; in special types of glass barium oxide (BaO): used to remove water from solvents; in the petroleum industry barium nitrate (Ba(NO 3 ) 2 ): used in fireworks; as rat poison; in special ceramic glazes Health effects Sir Humphry Davy WEBMASTER Sir Humphry Davy (1778-1829) Humphry Davywas born on December 17, 1778 in Penzance, Cornwall, England. He received his education in Penzance and in Truro. His father died in 1794, and Davy, in an effort to help support his family, became an apprentice to a surgeon-apothecary. Davy's most important investigations were devoted to electrochemistry.

Following Galvani's experiments and the discovery of the voltaic pile, interest in galvanic electricity had become widespread. The first chemical decomposition by means of the pile was carried out in 1800by Nicholson and Carlisle, who obtained hydrogen and oxygen from water , and who decomposed the aqueous solutions of a variety of common salts. Davy, too, began to example the chemical effects of electricity in 1800. He soon found that when he passed electrical current through some substances, these substances decomposed, (a process later called electrolysis). In 1813, Sir Humphry Davy concocted a giant battery in the basement of Britain's Royal Society. It was made of 2,000 pairs of plates and took up 889 square feet. The intensity of its effect (the voltage generated) was directly related to the reactivity of the electrolyte with the metal. Evidently, Davy understood that the actions of electrolysis and of the voltaic pile were the same. His work led him to propose that the elements of a chemical compound are held together by electrical forces.

Davy must have known of Lavoisier's suggestion that the alkali earths were s of unknown metals. At first, he tried to separate the metals by electrolyzing aqueous solutions of the alkalis, but this yielded only hydrogen gas. He then tried passing current through molten compounds, and his persistence was rewarded when he was able to separate globules of pure metal by this means. His first successes came in 1807 with the separation of potassium from molten potash and of sodium from common salt. He described potassium as particles which, when thrown into water , "skimmed about excitedly with a hissing sound, and soon burned with a lovely lavender light." Dr. John Davy, Humphry's brother, said that Humphry "danced around and was delirious with joy" at his discovery. These results were presented in the Bakerian lecture of November, 1807. Davy and corrosion monitoring Through electrolysis, Davy eventually discovered magnesium, calcium, strontium, and barium in 1808. For all these discoveries, much groundwork had of course been done by others.

Davy utilized the reducing power of potassium to prepare boron, and he developed the method of separating potassium from sodium based upon the insolubility of potassium perchlorate and the solubility of sodium perchlorate in 97% alcohol. In 1801, the Royal Institution in London engaged Davy as a public lecturer. Michael Faraday began attending Davy's lectures in 1810. In December, 1811, Faraday impressed Davy by sending him copious bound notes of these lectures, including exact drawing of Davy's apparatus. The previous October, Davy had been temporarily blinded by an explosion in his laboratory, and he needed help. He hired Faraday at once, beginning a close personal and professional association that lasted for years. Davy twice opposed the election of Faradayto fellowship in the Royal Society. At one point he objected to honoring Faraday for achieving the first liquefaction of chlorine, claiming that he himself deserved credit for the feat. Another time, Davy said his opposition was due to his belief that William Wollaston (1766-1828) had preceded Faraday in discovering electromagnetic rotation.

Perhaps Davy had simply become envious of his (successful) former assistant. Faraday did finally become a Fellow of the Royal Society in 1824. The first application of cathodic protection (CP) can be traced back to 1824 , when Sir Humphry Davy, in a project financed by the British Navy, succeeded in protecting copper sheathing against corrosion from seawater by the use of iron anodes. This limited use of CP on copper sheathing has endured and when wooden hulls were replaced by steel the fitting of zinc protector blocks on the sterns of naval vessels became traditional. These zinc slabs, although they offered some protection to steel hulls against local galvanic effects due to the presence of the bronze propellers, were generally not deemed to be effective. ( reference ) Davy's chemical lectures and demonstrations were brilliantly presented and became a fashionable social event. He also lectured and wrote a book on agricultural chemistry and presented the first systematic geology course offered in England. His first Bakerian Lecture won a prize from Napoleon, even though France and England were at war. In 1827, Davy became seriously ill. The illness was later attributed to his inhalation of many gases over the years.

In 1829 he made his home in Rome. While in Rome, he had a heart attack and he later died on May 29, 1829in Geneva, Switzerland. ( reference )

Question: Who in 1807 & 1808 was the first to discover and isolate the metals sodium, potassium and calcium?
Answer: SIR HUMPHREY DAVY